Abstract

The hysteresis mechanism is studied in pentacene organic thin-film transistors (OTFTs) with poly(4-vinyl phenol) (PVP) gate insulator by examining OTFTs with an oxide/PVP double layer gate insulator. The oxide thickness affects the direction of the hysteresis as well as its magnitude. This result can be explained on the basis of the charge injection and trapping mechanism rather than slow polarization or ion migration. The hysteresis occurs mainly due to the charges which could be injected from the gate electrode and trapped in the PVP. As the thickness of the oxide layer is increased, the gate charge injection is blocked and the effect of the charges from the channel increases.